Process of manufacturing gelatin blasting explosive



Patented May 22, 1951 UNITED STATES ATENT OFFICE PROCESS OFMANUFACTURING GELATIN BLASTING EXPLOSIVE Stanley Fordham, Saltcoats,Scotland, assignor to Imperial Chemical Industries Limited, acorporation of Great Britain No Drawing. Application February 3, 1947,Se-

rial No. 726,227. 1946 i 4 Claims.

In Great Britain March 14,

The present invention relates to the manufac- I prising nitrocellulosein solution in one or more liquid explosive nitric esters to render theexplosive capable of being cartridged by extrusion. The most powerful ofthe gelatine blasting explosive compositions, known as blastinggelatine, consists of practically undiluted nitroglycerine jelly, andthere is also available a series of less powerful explosives whichcomprise vegetable tissue materials of more or less porous structure andof oxidisable character and oxidising salts, for instance woodmeal andinorganic nitrates distributed through a liquid explosive nitricester-nitrocellulose jelly.

As is well known wet nitrocellulose is frequently used for gelatineblasting explosives and this may contain 30% or more water. Whennitrocellulose is added in this form to liquid nitric esters there is atendency to form pips.

The object of the present invention is to provide a process forproducing more homogeneous gelatine blasting explosives having wetnitrocellulose incorporated therein than have been produced heretofore.

I have now found that the inclusion of a wetting agent amongst theingredients of the gelatine blasting explosive that contains wetnitrocellulose results in a marked diminution in the occurrence of pipsin the final product.

According to the present invention, therefore, a gelatine blastingexplosive containing wet nitrocellulose has a wetting agent distributedthrough said explosive.

The process according to the invention for the production of a gelatineblasting explosive comprises mixing wet nitrocellulose, soluble innitroglycerine, and one or more liquid explosive nitric esters in thepresence of a Wetting agent.

Almost any anionic or non-ionic agent may be used which is preferablyadded to the water of the nitrocellulose if water-soluble or to theliquid explosive nitric ester if water-insoluble. For instance,non-ionic agents as for example polyglyceryl ricinoleate may bedissolved in the liquid nitric ester in the preparation of gelatineblasting explosives. On the other hand, it is necessary for an anionicwetting agent as for example sodium dibenzyl sulphanilate or the sodiumsalt of isopropyl napthalene sulphonic acid to be in solution in thewater associated with the nitrocellulose prior to mixing the saidnitrocellulose with the liquid explosive nitric ester. The best resultshave so far been obtained by having in solution up to 5% of a sulphonatewetting agent in the water. associated with the nitrocellulose.

In a gelatine blasting explosive according to the inventien the quantityof wettin agent is preferably between 0.2 and 2% calculated on the drynitrocellulose present.

The term wetting agent is meant to include anionic or non-ionic organicwetting dispersing and emulsifying agents having the property ofassisting the wetting of nitrocellulose by water.

It is desirable that the initial mixing of the nitrocellulose and theone or more liquid explosive nitric esters and wetting agents shouldtake place in the absence of any gelatinisation accelerant.

The invention is illustrated by the following examples in which theparts are parts by weight. By the term blastin soluble nitrocelluloseused in the following examples is meant, the product obtained by thenitration of purified cotton cops by the pot process to a nitrogencontent of 11.95 to 12.15% and which is at least soluble in a mixture ofether and alcohol (66 O. P.) in the proportion by volume of 2:1 and hasa viscosity of to 300 c. g. s. units in 100 ml. acetone 95% at 20 C.

Example I Blasting soluble nitrocellulose in the course of itsmanufacture is given a last wash with a 1% aqueous solution of sodiumisopropyl naphthalene sulphonate. This is then pressed to a moisturecontent of 28%. The content of wetting agent is 0.4% calculated on thedry nitrocellulose. After breaking down the lumps the wet nitrocelluloseis mixed into a smooth gel with nitroglycerine without such precautionsas for example blending with inert material. This smooth el is suitablefor use as a base in the manufacture of blasting explosives.

Example II Blasting soluble nitrocellulose is given a last wash with a4% aqueous solution of sodium dibenzyl sulphanilate. This is thencentrifuged or pressed to a moisture content of 33%, and the lumpsbroken down. The content of wetting agent is about 2% calculated on thedry nitrocellulose. The resultant nitrocotton is used in the manufactureof gelatine blasting explosives, as

nitrocellulose) 1.5 Liquid nitrobody mixture 1: 8 Wood meal- 4.0 Oathusk meal i3. Ammonium nitrate 36.1 Sodium nitrate 19i0 The low-freezingnitroglycerine contains 4 parts nitroglycerine with 1 part ethylenevglycol dinitrate.

The nitrocellulose, woodmeal and cat husk meal are placed in a rubberlined box, and the nitroglycerine added. The whole are .a preliminarymixing by hand, and the liquid mitrobody .mixture then added. The jellythus obtained is allowed to'stand for at least-one hour, and thentransierred :to the bowlof a McRober-ts mixer. The stirrers are rotated,the ammonium nitrate and sodium :nitrate added, and the whole mixed for35 minutes at .20" C. The resultant explosive may he cartridged byextrusion, and is :completely uniform and tree from pips.

Example III ithe invention .may .be applied in the manuatacture :ofPolar Ammon vGre'lignite .of the .following composition:

The wetting agent, 'polyg-lyceryl ricinoleate, is dissolved in thenitrogly-cerine, which is then added to the wet nitrocellulose and Woodmeal in a rubber lined box. After a preliminary mixing by hand, theresultant jelly is allowed .to stand for one hour. The jelly is thenmixed -with the ammonium nitrate .and sodium nitrate and extruded, .asin Example II. .The resultant explosive is again uniform and free frompips.

I claim:

1. A process for the production of gelatine 'blas'ting explosives whichcomprises Lmix'in'g one part by weight of :water =wet nitrocellulose,0.2 to 2% byweightof a neutral organic wetting agent having the propertyof assisting the wetting of nitrocellulose by water and selected fromthe group consisting of sodium isopropyl naphthalene sulphonate, sodiumdibenzyl sulphanilate, and polyglyceryl .ricinoleate, and at .least .9parts by weight of at least one liquid .nitric ester, the weight of saidneutral organic wetting agent' bemg calculated on the basis of theweight of the dry nitrocellulose present.

2. A process 'for the production of gelatine blasting explosives whichcomprises mixing sodium z-isopropyl naphthalene sulphonate in a iQportion :of 012 to 2% by Weight with one part by weight of wetnitrocellulose and thereafter adding at least.9 parts by weight of atleast .one nitric .ester, the weight of sodium isopropyl naphthalenesulphonate being calculated on the basis of the weight of the drynitrocellulose present.

3. A process for the production of gelatine rblasting explosives whichcomprises mixin sodium dibenzyl sulphanilate .a proportion of 0.2 to 2%by weight with one part by weight of water wet nitrocellulose andthereafter adding at least .9 .parts :byzweight of at least one liquidnitric :ester, the weight of :sodium d-ibenzyl sulphanila-te beingcalculated .on .the basis of the weightzof the dry nitrocellulosepresent.

4. A process for the production at gelatine blasting explosives whichcomprises mixing polyglyoeryl ricinolea-te :in a proportion of 0.2 to21% by weight with at least -9 :parts by weight of at least-oneliquid-nitric ester, and thereafter adding one part by weight of waterwet nitrocellulose, the weight of the polyglyceryl ricinoleate beingcalculated on the basis of the weight of dry nitrocellulose present.

STANLEY FORDHAM.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,956,090 Fassnacht July .10,.1934 2,120,324 Dickerman June 14, 1938 2,121,138 Wiggam June 121., 19385 2,131,574 Tapley Sept. .27., 1938 2,235,298 Olsen Mar. 18, 19412,454,643 .Fordham Nov. 123, .1948

FOREIGN Number Country Date 28,974. Great Britain of 1911

1. A PROCESS FOR THE PRODUCTION OF GELATINE BLASTING EXPLOSIVE WHICHCOMPRISES MIXING ONE PART BY WEIGHT OF WATER WET NITROCELLULOSE, 0.2 TO2% BY WEIGHT OF A NEUTRAL ORGANIC WETTING AGENT HAVING THE PROPERTY OFASSISTING THE WETTING OF NITROCELLULOSE BY WATER AND SELECTED FROM THEGROUP CONSISTING OF SODIUM ISOPROPYL NAPHTHALENE SULPHONATE, SODIUMDIBENZYL SULPHANILATE, AND POLYGLYCERYL RICINOLEATE, AND AT LEAST 9PARTS BY WEIGHT OF AT LEAST ONE LIQUID NITRIC ESTER, THE WEIGHT OF SAIDNEUTRAL ORGANIC WETTING AGENT BEING CALCULATED ON THE BASIS OF THEWEIGHT OF THE DRY NITROCELLULOSE PRESENT.